United3dArtists Archive

clintonman · Post by **clintonman** » 07 Jan 2014, 05:51

I decided to start this thread to discuss rigging in trueSpace workspace and try to formalize some ideas.
Note that none of these observations include stretchy IK or morphs.

Did you know an IK handle can be used as a lock? Correction: IK handle is used as a lock assistant to improve the quality of a full lock.

The ik handle must be set with IK interpolation, Firm handle and Lock children.

Attached is a mp4 video showing the difference between a standard full lock and an ik handle acting as a lock. The scene file is also attached.

EDIT:

Just found out that a lock is needed during the animation process. So as shown it's good for playback but for animation the ik handle "lock" also needs a regular lock. The lock isn't associated with the "ik handle lock" it's just there in addition to it. So you do regular rig then add the special ik handle. Hope that makes sense.

EDIT: changed the image and updated the scene file to show and use the ik lock in addition to the ik handle as a lock assistant

clintonman · Post by **clintonman** » 07 Jan 2014, 05:59

Scaling a full lock will make the skeleton blow up.

Scaling position and rotation seems ok.

Scene attached.

v3rd3 · Post by **v3rd3** » 07 Jan 2014, 08:21

Thank you for this Clinton. I always appreciate the opportunity to learn from you.

Draise · Post by **Draise** » 07 Jan 2014, 13:46

IT'S CHRISTMAS!

Wow, this is reminiscent of my Odyssey with my Minlis Rig. I wish I knew all these. Good work for figuring it out! Those full lock systems really bugged me and ultimately (by accident) I would 'blow' my rig often - not to mention the swimming feet!

With my Minlis character I do have morphs and stretch bones though - you can look in my thread here. I have some points tested and others not so tested, but you can follow those points to see if they are relevant to formalize them or to just test them. I did find the scale blow up's it seems, among other difficulties that you might find once you start testing "squash and stretch" and morphs and animation.

Concerning the IK handle lock, can this be animated or have a blend weight value to FK again? My rig is somewhat buggy - but it's mainly due to the fact that I did not know about some of these tricks.

(For example, lock the IK joint, then blend it back to FK to animate it to another position to then lock?)

clintonman · Post by **clintonman** » 07 Jan 2014, 15:51

Draise wrote: ...
With my Minlis character I do have morphs and stretch bones though - you can look in my thread here.
...
Concerning the IK handle lock, can this be animated or have a blend weight value to FK again? My rig is somewhat buggy - but it's mainly due to the fact that I did not know about some of these tricks.

(For example, lock the IK joint, then blend it back to FK to animate it to another position to then lock?)

I'm not sure I understand can you post a picture or scene? And yes I've read your thread more than once. When I get to the point of stretchy ik and morphs I'll be reading it at the very least 3 or 4 more times.

clintonman · Post by **clintonman** » 08 Jan 2014, 04:24

I believe it's better to place handles at joints and locks on bones. The placement is more intuitive and it may be important when setting several handles on one joint. The image shows that clicking a joint centers the handle on the joint. If you click a bone then the handle is not centered where you click. If you click a bone to add a lock the lock appears on or near the bone. If you click a joint when adding a lock the lock will move to the center of a bone (the bone up the hierarchy?) .

EDIT: I change my mind about locks always going on bones. Position locks might be better in some cases on the joint instead of the bone and when you click to add them to a joint they are added at that location. This is what IK Handel does in his videos.

clintonman · Post by **clintonman** » 08 Jan 2014, 05:16

Multiple IK handles can be assigned to a joint. Images show 3 handles assigned to a joint. One for movement, one for lifting the heal and one for rotating the final bone in two directions. The IK handles had to be added at the joint as opposed to the bone so that the center of rotation was identical for the heel lift and the foot rotate motions and the rotations would be around the actual joint instead of somewhere on the bone.

clintonman · Post by **clintonman** » 08 Jan 2014, 05:23

Demo scene and video for the multiple ik handles on one joint. Note that the character maybe unstable since I deleted several bones to make the ik system easier to see for the screen capture images in the previous post. The circle IK handle at the ankle is used to help the full stop on the bone below it. The video has no audio. The position handle can be seen rotating with one of the rotation handles. This is because the handles were set to follow the bone by using the Align Inverse Kinematics Handle tool.

multipleIKhandles.zip is the video

multiHandleDemo.zip is the scene file

clintonman · Post by **clintonman** » 09 Jan 2014, 03:31

Align Inverse Kinematics handle tool. This one is in the manual but I kept missing it for some reason. Use it to make a handle follow a bone when it rotates instead of the default of just following the whole skeleton when it rotates.

Video and scene file attached.

Edit: alignIKhandle.mp4 Video too big for the forums. Link http://www.clintons3d.com/stuff/"

clintonman · Post by **clintonman** » 09 Jan 2014, 03:51

: ikHandleDefaults.jpg (14.57 KiB) Viewed 6769 times

: ikHandleBetter.jpg (13.23 KiB) Viewed 6769 times

IK Handle defaults are set for FK. An IK default is better for an IK handle so turn off Posing only and move the FK/IK Interpolation slider all the way to IK.

clintonman · Post by **clintonman** » 09 Jan 2014, 05:56

Keyframe Interpolations compared. The keyframe interpolation script was run on the animation to produce results from left to right of bezier(the default interpolation), flat and linear. The bezier shows the feet sliding. Flat stops the sliding feet but the hips have a stop and go action. Linear has the proper motion for the feet and the hips, but it has a more mechanical feel to it. The combined interpolation video shows constant hip motion and less mechanical steps. First the animation was set to flat interpolation with the script then the root joint was manually edited in the FCurve view by setting the y motion to linear interpolation.

walkInterpolations - shows the 3 types side by side

combinedInterpolation - flat interpolations with the root joint manually changed to linear interpolation

So for IK animations I think flat interpolation type is the best default with individual joints and channels set to linear to correct any stop and go motion caused by the flat interpolations. More tests are needed. I suspect that some combination of bezier and flat might work even better.

The keyframe interpolation script is found here: http://www.clintons3d.com/plugins/trues ... index.html"

Draise · Post by **Draise** » 09 Jan 2014, 20:33

Wow, these are great! I will sit through them all and try figure them out, maybe play with a little animation - or redo my Minlis Rig version 0.3! Genious. And I am very thankful for them.

Concerning the FK/IK blend.. you said you could turn a controller into an FK fixed point (that wont move around or slide - like a fixed controller?) but now I would like to learn if you could blend the fixed FK controller into a IK controller that might be animated (FK/IK controll).. I'll experiment and try show you if I can... not sure if I'm being clear.

Concerning your last video - are you suggestion (without using your foot placement plugin) that one can use a mixture of linear and normal keyframes to not get shifting feet on the ankle pivot joint kyeframes? (for example)

clintonman · Post by **clintonman** » 10 Jan 2014, 06:32

Draise wrote:Wow, these are great! I will sit through them all and try figure them out, maybe play with a little animation - or redo my Minlis Rig version 0.3! Genious. And I am very thankful for them.

Concerning the FK/IK blend.. you said you could turn a controller into an FK fixed point (that wont move around or slide - like a fixed controller?) but now I would like to learn if you could blend the fixed FK controller into a IK controller that might be animated (FK/IK controll).. I'll experiment and try show you if I can... not sure if I'm being clear.

Concerning your last video - are you suggestion (without using your foot placement plugin) that one can use a mixture of linear and normal keyframes to not get shifting feet on the ankle pivot joint kyeframes? (for example)

Yes. Linear keyframes alone will get rid of any shifting motion in the IK and other joints/channels not controlled by IK can be set to non-linear via the FCurve editor for a smoother result. It's all experimental at this stage but it looks promising.

clintonman · Post by **clintonman** » 11 Jan 2014, 04:40

Piston rig.

The IK handle on the right is connected to joint at the end of the chain on the left and the IK handle on the left is connected to the end joint on the right. A watchdog and a custom script makes the handles follow the position of the joints on the far left and right.

The system only works if the joint is selected or the Watch Dog is visible in the link editor. The joint WldMatrix is the input to the Watch Dog node. The Watch Dog Regulator stops the script from firing too often.

At first I tried using the lookat tool, but it doesn't work properly inside of a actor/skeleton.

Edit: Oops, forgot to attach the scene file

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